Friction Stir Welding is a solid state join process in which the heat need is produced by the friction of a tool on the work pieces. The tool rotates on the surface and also applies a force against it to create the needed friction. This technology does not use any consumable and does not produce any gas, which makes it cost effective, save for the operators and clean.

The equipment used for this technology has been changing within the years. Milling machines were adapted to it at the beginning. After, specific machines for friction stir welding were developed, providing higher down force and control systems. Nevertheless, the lack of flexibility of machines made industrial robots became an alternative. Robots have limitations in terms of stiffness. But, they can be used to weld complex geometries and they can be used in large scale applications due to their flexibility and low cost.

This project studies the process from the robot behaviour perspective. The main objective is to achieve a better understanding of the process to contribute to the continuous development of robotic FSW. An acquisition system was developed to monitor different signals from the robot such as, forces, torque, path deviation, and vibrations. The data acquisition system developed and mounted at PTC was tested and its limitations were examined. The developed system has been used for conducting different experiments: The differences between the robot system and a system based on a FSW machine situated at TWI were studied; and, in addition, the behaviour of the robot under different welding parameters was investigated.